Fish hatchery
From Wikipedia, the free encyclopedia
Fish hatcheries are used to cultivate and breed a large number of fish in an enclosed environment,
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[edit] Function
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Fish Hatcheries typically involve a lot of manual labour. A hatchery worker will take a female fish, release her eggs (stripping), and then externally add the male fish's sperm (milt), mix them and allow them to fertilize and incubate undisturbed, where there is less risk of disease or predation. They can immediately dispose of any unfertilized eggs. What happens next depends on the purpose of the Hatchery. Fish farms use Hatcheries to cultivate fish to sell for food, or ornamental purposes, eliminating the need to find the fish in the wild and even providing some species outside of their natural season. They raise the fish until they are ready to be eaten or sold to aquarium stores. Other Hatcheries release the juvenile fish into a river, lake or the ocean to support commercial, tribal, or recreational fishing or to supplement the natural numbers of threatened or endangered species, a practice known as fish stocking. Some fish Hatcheries are used to mitigate the effects of development, such as construction of a dam, hydroelectric plant or water diversion. In the United States and Canada, these hatcheries usually raise anadromous fish that are unable to migrate due to the obstruction, particularly salmon and steelhead. In 1889 a cod fish hatchery was erected on an island belonging to Newfoundland and Labrador. It was the largest hatchery in the world at that time and the first in North America. The ornamental fish industry uses fish hatcheries to produce fish for the aquarium fish trade, this has helped to limit the over harvesting of native fish populations both in fresh and salt water ecosystems.
[edit] Criticisms
Originally devised to mitigate for fish production lost through development and supply the demand for fishing from an expanding human population, fish hatcheries have been causing problems by producing poor quality or genetically inferior fish. Several researchers have raised concerns about hatchery fish potentially breeding with wild fish. Hatchery fish may in some cases compete with wild fish. [1] There is lively debate among the scientific community regarding the risks and benefits of hatchery programs. Proving negative (or positive) effects of hatchery programs on wild fish is challenging due to numerous other environmental and anthropogenic factors that simultaneously affect fish. In the United States and Canada, there have been several salmon and steelhead hatchery reform projects intended to reduce the possibility of negative impacts from hatchery programs. Most salmon and steelhead hatcheries are managed better and follow up to date management practices to ensure any risks are minimized.
[edit] See also
[edit] References
- ^ Genetics and the Extinction of Species, Laura F. Landweber and Andrew P. Dobson eds., Princeton University Press (1999)
[edit] External links
- Hatcheries and the Protection of Wild Salmon
- University of Washington Libraries Digital Collections -- Digital Collections -- Fish Hatcheries An ongoing digital collection of images related to fish hatcheries.
- [1] - Links to hatchery reform projects
